My understanding is that the very notion that the Mongols retreated from Europe because of Ogedei's death is considered suspect today.
One could very credibly argue that the Mongol campaign in Europe ended because the Mongols were defeated - not in a single pitched battle, but over several seasons of grueling sieges, poor weather, and dogged resistance by holdouts in Hungary and Croatia - in which case the answer to "how far could they have gotten if Ogedei had lived" is "exactly as far as they did."